Mechanical assemblies are generally made by way of fasteners, such as screws, nuts and bolts, rivets and the like, which are used for holding together the diverse parts forming the mechanical assembly. A problem generally associated with conventional fasteners is that they are generally weaker than the parts held in assembly, they do not permit to control with precision the amount of mutual pressure exerted by the mechanical parts being joined or the amount of torquing of a bolt or a nut, they often require some auxiliary locking devices or "safeties" in assemblies subjected to stress or vibrations which may loosen the fastener, and are subject to other inconveniences and failures, all well known to those skilled in the art of fasteners.
Another problem associated with conventional fasteners such as screws, nuts and bolts, even when provided with auxiliary locking devices, is that they can easily be unfastened or removed by unauthorized persons. Such is the case with respect to fasteners holding access cover plates to mechanical, electronic or electrical devices, or to instruments, meters and the like, where it is desired to protect from inspection or interference with by unauthorized persons. Another example of assemblies generally using conventional fasteners which are desirable to be protected from interference by unauthorized persons, are locks, doors and window hinges, such that the mounting screws for locks and hinges are usually disposed on the inside of a building such as to be inaccessible from the outside. It is not, however, always possible to mount door hinges on the inside, as is the case when doors must open towards the outside of the building because of fire regulations.
The shortcomings and inconveniences of conventional fasteners are remedied by the present invention which provides fastening means which permit to hold parts in assembly with any degree of pre-load or pressure desired, which are not subject to loosening as a result of variable loads or vibrations being applied to the assembled parts and which, according to an aspect of the invention, prevent unauthorized disassembly or removal of the parts by means of ordinary tools.